Selective load energization



SELECTIVE LOAD ENERGIZATION Filed Sept. 4. 1953 F'IG.2.

2 Sheets-Sheet 2 CATHODE 88 l 86 --{:87 89 87 INVENTOR.

JOSEPH J. SAY KAY RNEYS.

United States Patent O 1 2,939,121 v .SELECTIVE LOAD ENERGIZATION Filed Sept. 4, 1953, Sex. N0. 378,475 2 Claims (C1. 340-176) This invention relates to apparatus for energizing selected load means and, more particularly, pertains t'o such apparatus employing rectifier stacks.

My co-pending application Serial N0. 178,186, filed August 8, 1950, for Electrical Keyboard, 110W Patent N0. 2665336, discloses circuits that employ a plurality cf stacks of rectifiers, connected in parallel relation, for generating a desired number of coded electrical impulses to be utilized in communications equiprnent. With the use of such rectifier stacks, much of the complicated mechanical apparatus formerly .necessaxy has been obviated resulting in asimple, inexpensive keyboard. Although the foregoing circuit arrangements have been advantageous, certain difficulties have arisen with the pralleling of large numbers of rectifiers. 'Primarily, the system operates due to the dilferential between the W forward resistance and the high back resistance of the-rectifiers. However, when many rectifiers re disposed in parallel, the combined leakage current through the back resistance becomes a substantial current flow and occasionally causes the energization of unselected load means. k

It is a primary object of the preseut invention, accordingly, to provide electn'cal circuits including stacks cf rectifiers for kanergizingselected load means irrespective of the number of paralleled rectifiers.

This and further objects are accomplished in one embodim ent of the invention by paralleling a plurality of stacks of rectifiers for controlling a plurality of relays. Upon the selective operation of one or more of these relays through a rectifier stack, a control relay will be energized to prevent the further operation of any unselected relays by leakage currents. However, the se leoted relay or relays will remain excited through an alternate=energizing path completed upon their actuation.

In another embodiment of the invention, gas diodes may be selectively energized by :the rectifier stacks', and since a certain threshold voltage is required therea cross to ionize the gas, the diodes Will conduct onlyupon the coupling of a voltage source thereto through the forwardly directed retifiers, the voltage across the'diodes due rto leakage current in the backward directionbeing insuflicient to cause any difficulties.

In still another embodiment of the invention the properties of gas triodes, commonly termed thyratrons, may be advantageously utilized. Thus, the thynatrons will =be provided with a striking voltage at the grids thereof only upon the coupling of a voltage source thereto through the forwardly directed rectifiers, the voltage due to the leakage current in the back direction again being insuflicient to strike the tubes.

These and further objects and advantages of the invention will be more readily understood when the following description is read in connection with the accompanying drawings in which:

Fig. 1 is a schematic diagraxn cf one form ofcircuit embodying the present invention;

2,939,121 Pitented My 31, 1960 Fig. 2 is a schemzttic diagram of a circuit helpful in describing certain pn'nciples of the inventioxi;

Fig. 3 is a schematic diagram of anothet form of circuit embodying the invention; and

Fig. 4 is a partial schematic diagram 0f a further eifcuit embodying the invention.

Refern'ng to the drawings and p2irticularly to Fig. l, a representative schematic circuit embodying the preSent invention is illustrated. A power source 10, shown here as a battery, has its positive terminal conuected through conductors 11 and 11a to a plurality of sWi-tches 12, illustrated schematically only and which may take any convenient form depending upori their manner of actuation. F01 example, they may be plunger actuated by the striking of a keyboard or cam actuated -by a key striking linkage found in a conventional typewriter.

Connected to one contact of each of the swi-tches 12 by a conductor 15 is a rectifier stack 13 consisting of at least one rectifier 14, preferably of the well known selenium type. It is obvious that other conventional rectifiers may be employed such as the copper Oxide and high vacuum types. Joining the stacks 13 are couductors 16, tonnected to the rectifiers 14 in a prede termined man'ner to picvide the necessary oode oombina tions. Although only seven rectifier stacks 13 are illustrated in Fig. 1, the employment of asmany stacks as necessary is corltemplated. Thus, with six conductors 16, there are siXty-four different combinations of rectifiers possible if a bin'ary code is contemplated and if desirable, all sixty-four may be utilized which would oa.ll for a like nulnber of stacks' 13.

Bach of the conductors 16 is connected thxough a load device 16a, comprising any desired electro-responsive element, to an energizing winding of a relay 17 having a pair of interconr'1ected armatures 18 and 19 eng-aging, when energized, relaycoutacts 20 and 21, respectively. The energizing circuit for each of the relays 17 is normally completed through a conductor 22, a relay contact 23, an armature 24 and conductors 25 and 26 to the negative terminal of the power source 10.

Also connected to the positive terminal of the power source 10 :through the conductor 11 and a conductor 11b is a control relay 27, which upon energization, actua-tes mechanically interconnected armatures 24 into engagement with relay c0ntacts 28. The electrical circuit for the control relay 27 is comPleted through a conductor 29, one of the armatures 19 engaging the corresponding contact 21 and the conductors 25 and 26 to the negative terminal of the power source 10.

In describing a typical operation 01 the embodiment of the invention illustrated in Fig. l, reference will be made to Fig. 2 to aid in understanding the necessity for the contr0l relay 27 and the circuits associated therewith. Five rectifier Stacks 50 -to 54, inclusive, are illustrated in Fig. 2, and are joined by conductors 55 to five' relays 56 to 60, respectively. A power source 61 having a potential of, for example, 24 volts, is selectively counected through switches 62 to 66, inclusive, to the rectifier stacks. It will be assumed in the opcration of this circuit that the relays 56 to 60 are 24-volt relays requiring milliamperes cf current for energization. It will also be assumed that a leakage current of 1 milli ampere will flow in the back direction through the rectifiers when the power source 61 is impressed thereacross in the reverse direction.

In the operation cf the circuit shown in Figl 2, closing parallel relation, each of said stacks including at least one of said rectifiers, a source cf: electrical energy, a plurality of relays coupled to said stacks and to said source, means for selectively coupling said source to at least one cf said stacks for energizing a selected number of said relays, means responsive to the energization cf said selected number of said relays for disconnecting the unselected relays from said source, and means to provide a holding circuit for each of said energu'zed relays.

2. In electrioa.l apparatus, the combination of a plurality cf stacks cf rectifiers, said Stacks being connected in parallel relation, a source of electrical energy, means for selectively joining said sonne to each of said stacks, a plurality of relays coupled to said stacks and to said 6 source, switohing means for interrupting the coupling of said relays to said source, relay means responsive to the energization of at least one of said relays for operating said switching means, a.nd means to provide a holding circuit for each cf said energized relays.

References Cited in the file of this patent UNITED STATES PATENTS 876,701 Drewell Jan. 14, 1908 2549,779 Crenshaw Apr. 24, 1951 2686299 Eckert Aug. 10, 1954 2688661 Van Mierlo Sept. 7, 1954 FOREIGN PATENTS 363,696 Great Britain Dec. 21, 1931 666,314 Great Britain Feb. 13, 1952 OTHER REFERENCES Publication, Proceedings of the I.R.E. Feb. 1949, Title of Rectifier Networks for Multipositiom'ng Switching, by Brown -and Rochester, pp. 139-147. 

